Slight aggressiveness in my chicken

That is not aggression towards you, just desire for what you are carrying - food. They are probably getting used to you and feel more comfortable getting up close. They can be grabby sometimes.

 

Are they getting enough food? A few months back my girls were a lot more aggressive when I was giving them treats. Later that day I noticed that their feeder had clogged...

 

No matter how well fed chickens are always starving when you bring in more food even if it's what is in the feeder. When you refill their feeder if they get aggressive take your finger and peck the most aggressive one on top of the head once or twice and work your way down the list till they quit. The big dog in the coop doesn't put up with that kind id behavior and this they understand. You never see a hen pecking on the top rooster at least not for long. Some hens may still peck at things to check them out because that is how they learn about things but aggressive behavior should not be allowed.
The pushing away probably won"t stop them if you'll watch your girls when they all want to eat you'll see the hens pushing their way in to the food.The girls that get pushed aside don't just give up they circle and attack from a different angle, their used to this as normal but a peck on the head gets their attention. If you do this tho you have to mean it a little push peck won't even phase them. I'm not saying to hurt them but get their attention and let them know you mean business. Just one quick peck and ignore them if they quit, you've made your point.

 

Let me put it this way. If you were at the mall, and someone was walking down the concourse giving out free ice cream, wouldn't you crowd around and get excited and even competitive to make sure you got in on the free ice cream?

All creatures who depend on a continual intake of food for survival will get excited and competitive when food suddenly appears, especially if it's food that is craved.

 

Agrees...don't allow this behavior. Finger pecks on the head or pushing away(not gently) worked for me with the greedy ones when giving treats.
They may also still be unsettled in the new place, but don't let them abuse you...let them know that you are top hen.

Is it when you are refilling the feeder or when you bring the feeder back out after it having been gone all night to avoid the vermin?
What are you feeding them, protein percentage?